This invention relates to an explosively actuated overspeed decoupler for disconnecting a rotary driven member from a driving member.
While the invention is not limited to any particular application, in certain pumping installations it is necessary to decouple the motor from a pump in the event of failure in the hydraulic system. Such failure may make it possible for pumped water or other fluid under high pressure to flow through the pump operating the pump as a turbine to overdrive the motor at an excessive speed.
Available decoupling devices are not suitable for the present purpose. The decoupler must be precise in its response to overspeed, insensitive to acceleration, completely reliable in operation and must have various other qualities to suit the present purpose.
Objects of the invention are, therefore, to provide a decoupler which effects positive torsional decoupling at a precise overspeed, to provide a decoupler which is operable in either direction of rotation, to provide a decoupler which maintains the axial length and transverse stiffness and rigidity of a spool-type coupling, to provide a decoupler which maintains the driving and driven parts in alignment while supporting an axial thrust load either in tension or in compression, to provide a decoupler having a mechanically rugged and symmetrical configuration of elements, to provide a decoupler having an energy absorbing system which controls safely the motions of the coupling parts after the decoupling action takes place, to provide a decoupler capable of functioning within one to two milliseconds after overspeed reaches a preset limit, to provide a decoupler that is insensitive to rotational accelerations and/or seismic forces and will respond only to a preset absolute rotational velocity, to provide a decoupler having redundant overspeed sensing means and redundant actuating means either of which is capable of completing the decoupling action, and to provide such a decoupler which can safely withstand simultaneous operation of both redundant explosive decoupling actuator systems.